Chromosome 6 phylogeny in primates and centromere repositioning
Chromosome 6 phylogeny in primates and centromere repositioning
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DOI：
10.1093/molbev/msg165
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发表时间：
2003-09-01
影响因子：
10.7
通讯作者：
Archidiacono, N
中科院分区：
文献类型：
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作者：
Eder, V;Ventura, M;Archidiacono, N
15个人类BAC/PAC探针覆盖了整个6号染色体，用于对类人猿、旧大陆猴、新大陆猴和狐猴的代表进行FISH实验，以描绘灵长类动物的6号染色体系统发育。家猫被用作外群体。分析结果表明，灵长类祖先的6号染色体结构与所有被研究物种的6号染色体结构相一致，只需很少的重排就能使其保持高度的标记顺序守恒。然而，与这个简单的进化场景相反，着丝粒被发现位于三个不同的区域，没有任何证据表明染色体重排可以解释它的运动。两个着丝粒重新定位事件中的一个发生在类人猿祖先。在将灵长类祖先的标记顺序与Catarrhini祖先区分开来的反转事件发生后，着丝粒从6p22.1移动到现在的位置。在6p22.1处发现了一组染色体内片段复制，分布在约9 Mb的区域，我们将其解释为祖先着丝粒两侧的双影体的遗迹。因此，我们的数据表明，在非着丝粒/非端粒位置发现的一些双象簇可能代表着在着丝粒重新定位发生后失活的进化沉默着丝粒的痕迹。此外，我们在旧大陆猴子中记录的6q24.3的新中心粒出现似乎在不影响移位的侧翼序列的情况下出现和发展。
A panel of 15 human BAC/PAC probes, covering the entire chromosome 6, was used in FISH experiments on great apes and on representatives of Old World monkeys, New World monkeys, and lemurs to delineate the chromosome 6 phylogeny in primates. The domestic cat was used as an outgroup. The analysis showed a high marker order conservation, with few rearrangements required to reconcile the hypothesized chromosome 6 organization in primate ancestor with marker arrangement in all the examined species. Contrary to this simple evolutionary scenario, however, the centromere was found to be located in three distinct regions, without any evidence of chromosomal rearrangement that would account for its movement. One of the two centromere repositioning events occurred in great apes ancestor. The centromere moved from 6p22.1 to the present day location after the inversion event that differentiated marker order of the primate ancestor from the ancestor of Catarrhini. A cluster of intrachromosomal segmental duplications was found at 6p22.1, scattered in a region of about 9 Mb, which we interpret as remains of duplicons that flanked the ancestral centromere. Our data, therefore, suggest that some duplicon clusters found in noncentromeric/nontelomeric locations may represent traces of evolutionary silenced centromeres that inactivated after the occurrence of a centromere repositioning. In addition, the neocentromere emergence we have documented in Old World monkeys at 6q24.3 appears to have arisen and progressed without affecting the displaced flanking sequences.